Recently, as a display device appropriate to thinning and enlargement, liquid crystal display devices using a liquid crystal display panel and plasma display devices using a plasma display panel (hereinafter referred to as “PDP”) have received attention and have been mass-produced, and the sale of them has hugely expanded.
A PDP is formed of a pair of glass substrates of a front plate and a back plate. The front plate has a display electrode pair, a dielectric layer, and a protective layer on the front glass substrate. The back plate has a data electrode, a barrier rib, and a phosphor layer on the back glass substrate. The front plate and back plate are faced to each other so that a micro discharge space is formed between them, and the peripheral parts of the front glass substrate and the back glass substrate are sealed with a sealing member. The discharge space is filled with discharge gas obtained by mixing neon (Ne) and xenon (Xe).
A metal plate as a chassis member is stuck on the back surface of the back plate of the PDP via an adhesive heat conductive sheet or a joint member such as an adhesive. The metal plate is a substrate to which an electric circuit member mounted with a driving circuit for driving the PDP is attached, and also has a function of efficiently radiating the heat generated in the PDP. The plasma display device is mounted with a front frame and back cover for protecting the PDP and electric circuit member.
Recently, as a great number of plasma display devices have become widespread, the number of used plasma display devices to be scrapped dramatically has increased. In this situation, the following treatment has become important from the viewpoint of an environmental issue and resource saving: a plasma display device including a failure caused in the manufacturing process and a used plasma display device that comes to the end of the product life to be scrapped are disassembled in a state where various members and materials are reusable at a low cost.
In order to disassemble a plasma display device in a reusable state, the plasma display device needs to be divided into a PDP mainly formed of a glass substrate, a metal plate as a chassis member, and an electric circuit member.
Conventionally, as a method of separating the PDP, metal plate, and electric circuit member from each other, the following documents are disclosed:                a method of physically cutting and separating a joint member with a cutting tool such as a cutting edge (for example, patent literatures 1-3); and        a method of cutting an attaching member for attaching the electric circuit member to the metal plate (for example, patent literature 4).        
However, as the screen and size of a display device such as a plasma display device have been increased, the scale of a device for separation has increased and the joint area between the PDP and the metal plate has increased. Therefore, an excessive peeling force needs to be applied when they are separated from each other in the disassembling process. It therefore becomes difficult to take a physical action uniformly over the whole surface of a large display device. Disadvantageously, the glass substrate forming the PDP breaks, the productivity in a subsequent process of separating the glass substrate is reduced, or a failure occurs in recovering the material.
When the attaching member disposed in the metal plate is cut in order to separate and disassemble the electric circuit substrate from the metal plate of the chassis member, the load during cutting is un-uniform because the attaching member is arranged irregularly on the metal plate. Therefore, a cutting failure or cutting time loss occurs, the productivity and efficiency reduce in disassembling the display device, disadvantageously.
[Patent Literature 1] Unexamined Japanese Patent Publication No. 2004-184677
[Patent Literature 2] Unexamined Japanese Patent Publication No. 2006-330205
[Patent Literature 3] Unexamined Japanese Patent Publication No. 2006-243184
[Patent Literature 4] Unexamined Japanese Patent Publication No. 2006-320783